Abstract: 【Aim】 This study aims to investigate the anatomical organization of the central nervous system of Apolygus lucorum (Hemiptera: Miridae) and to characterize the morphology, volume, spatial relationship and fusion pattern of the composed ganglia. 【Methods】 Immunohistochemical staining with synaptic protein antibody was used to label the neuropil of the central nervous system. Digital images of the central nervous system were obtained by using a confocal laser scanning microscope, and the three-dimensional models were constructed by using an image analysis software. 【Results】 The anatomical 1observation indicated that the central nervous system of A. lucorum consists of four main ganglia. From anterior to posterior, they are the brain, suboesophageal ganglion, prothoracic ganglion and posterior ganglion. The first three ganglia are fused together, forming a brain-suboesophageal ganglion-prothroracic ganglion complex. Such a complex has been found in insects for the first time. The posterior ganglion is linked to prothoracic ganglion by a long paired connective. Viewed from the external morphology, the central nervous system of A. lucorum is composed of two large ganglionic masses, a brain-suboesophageal ganglion-prothroracic ganglion complex and a posterior ganglion. Based on the synaptic staining, three neuromeres in the brain, three in suboesophageal ganglion, three in posterior ganglion and one in prothoracic ganglion were identified. The three neuromeres of the brain are protocerebrum, deutocerebrum, and tritocerebrum. The suboesophageal ganglion is composed of mandibular, maxillary, and labial neuromeres, while the posterior ganglion is fused with mesothoracic, metathoracic, and abdominal ganglia. 【Conclusion】 The results demonstrate that the central nervous system of A. lucorum is composed of the brain, suboesophageal ganglion, prothoracic ganglion and posterior ganglion, showing highly fused pattern. The results provide the morphological data for the studies of development, plasticity and evolution of the central nervous system, as well as a framework for investigating the morphology, disposition and function of the neurons which are involved in a specific regulation for insect physiology and behavior.

Key words: Apolygus lucorum, brain, suboesophageal ganglion, prothoracic ganglion, posterior ganglion, anatomical structure, three-dimensional model